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From: Stanislav Yakovlev <stas.yakovlev@gmail.com>
To: linville@tuxdriver.com
Cc: linux-wireless@vger.kernel.org, stable@kernel.org,
	656813@bugs.debian.org, s.L-H@gmx.de,
	Stanislav Yakovlev <stas.yakovlev@gmail.com>
Subject: [PATCH] net/wireless: ipw2200: Fix WARN_ON occurring in wiphy_register called by ipw_pci_probe
Date: Mon, 16 Apr 2012 06:38:30 -0400
Message-Id: <1334572710-10838-1-git-send-email-stas.yakovlev@gmail.com> (sfid-20120416_123434_240784_D20B8272)
Sender: linux-wireless-owner@vger.kernel.org
List-ID: <linux-wireless.vger.kernel.org>

The problem was found by Stefan Lippers-Hollmann
http://marc.info/?l=linux-wireless&m=132720334512946&w=2

WARNING: at /tmp/buildd/linux-aptosid-3.2/debian/build/source_i386_none/net/wireless/core.c:562 wiphy_register+0x45/0x38d [cfg80211]()
Hardware name: TravelMate 290 \xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff
Modules linked in: ipw2200(+) iTCO_wdt libipw joydev drm snd_seq snd_timer snd_seq_device iTCO_vendor_support yenta_socket snd intel_agp i2c_i801 pcmcia_rsrc cfg80211 soundcore parport_pc psmouse parport rng_core snd_page_alloc serio_raw pcspkr i2c_algo_bit intel_gtt pcmcia_core evdev irda crc_ccitt rfkill lib80211 processor container ac battery shpchp pci_hotplug button ext4 mbcache jbd2 crc16 dm_mod sd_mod sr_mod crc_t10dif cdrom ata_generic pata_acpi ata_piix libata scsi_mod firewire_ohci firewire_core crc_itu_t 8139too 8139cp mii uhci_hcd ehci_hcd usbcore usb_common [last unloaded: scsi_wait_scan]
Pid: 328, comm: modprobe Not tainted 3.2-1.slh.4-aptosid-686 #1
Call Trace:
[<c012eaf4>] ? warn_slowpath_common+0x7c/0x8f
[<e0ff0b3e>] ? wiphy_register+0x45/0x38d [cfg80211]
[<e0ff0b3e>] ? wiphy_register+0x45/0x38d [cfg80211]
[<c012eb22>] ? warn_slowpath_null+0x1b/0x1f
[<e0ff0b3e>] ? wiphy_register+0x45/0x38d [cfg80211]
[<c01f89d7>] ? internal_create_group+0xf5/0xff
[<e0a2de1c>] ? ipw_pci_probe+0xa9a/0xbd0 [ipw2200]
[<c01519f4>] ? arch_local_irq_save+0xf/0x14
[<c0252986>] ? pci_device_probe+0x53/0x9a
[<c02c2820>] ? driver_probe_device+0x94/0x124
[<c0252871>] ? pci_match_id+0x15/0x34
[<c02c28f0>] ? __driver_attach+0x40/0x5b
[<c02c1d81>] ? bus_for_each_dev+0x37/0x60
[<c02c25aa>] ? driver_attach+0x17/0x1a
[<c02c28b0>] ? driver_probe_device+0x124/0x124
[<c02c22c4>] ? bus_add_driver+0x92/0x1d1
[<e099d000>] ? 0xe099cfff
[<c02c2cb8>] ? driver_register+0x7d/0xd4
[<c017cd50>] ? jump_label_module_notify+0xec/0x167
[<e099d000>] ? 0xe099cfff
[<c0253017>] ? __pci_register_driver+0x32/0x87
[<e099d000>] ? 0xe099cfff
[<e099d02e>] ? ipw_init+0x2e/0x72 [ipw2200]
[<c0101173>] ? do_one_initcall+0x7d/0x132
[<c0145016>] ? __blocking_notifier_call_chain+0x47/0x4f
[<c0154a73>] ? sys_init_module+0x13a4/0x159c
[<c03a639f>] ? sysenter_do_call+0x12/0x28

This warning appears only if we apply Ben Hutchings' fix
http://marc.info/?l=linux-wireless&m=132720195012653&w=2
for the bug reported by Cesare Leonardi
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=656813
with cfg80211 warning during device registration
("cfg80211: failed to add phy80211 symlink to netdev!").

We separate device bring up and registration with network stack
to avoid the problem.

After that Ben Hutchings' fix can be applied to fix the bug.

Cc: stable@kernel.org
Signed-off-by: Stanislav Yakovlev <stas.yakovlev@gmail.com>

---

Stefan, can you test it once again?
---
 drivers/net/wireless/ipw2x00/ipw2200.c |   21 ++++++---------------
 1 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/ipw2x00/ipw2200.c b/drivers/net/wireless/ipw2x00/ipw2200.c
index f37d315..4130802 100644
--- a/drivers/net/wireless/ipw2x00/ipw2200.c
+++ b/drivers/net/wireless/ipw2x00/ipw2200.c
@@ -11432,20 +11432,6 @@ static void ipw_bg_down(struct work_struct *work)
 	mutex_unlock(&priv->mutex);
 }
 
-/* Called by register_netdev() */
-static int ipw_net_init(struct net_device *dev)
-{
-	int rc = 0;
-	struct ipw_priv *priv = libipw_priv(dev);
-
-	mutex_lock(&priv->mutex);
-	if (ipw_up(priv))
-		rc = -EIO;
-	mutex_unlock(&priv->mutex);
-
-	return rc;
-}
-
 static int ipw_wdev_init(struct net_device *dev)
 {
 	int i, rc = 0;
@@ -11714,7 +11700,6 @@ static void ipw_prom_free(struct ipw_priv *priv)
 #endif
 
 static const struct net_device_ops ipw_netdev_ops = {
-	.ndo_init		= ipw_net_init,
 	.ndo_open		= ipw_net_open,
 	.ndo_stop		= ipw_net_stop,
 	.ndo_set_rx_mode	= ipw_net_set_multicast_list,
@@ -11841,6 +11826,12 @@ static int __devinit ipw_pci_probe(struct pci_dev *pdev,
 		goto out_release_irq;
 	}
 
+	if (ipw_up(priv)) {
+		mutex_unlock(&priv->mutex);
+		err = -EIO;
+		goto out_remove_sysfs;
+	}
+
 	mutex_unlock(&priv->mutex);
 	err = register_netdev(net_dev);
 	if (err) {
-- 
1.7.2.5